1. Field of the Invention
This invention relates in general to advertisement signs, and in particular to sign opening, closing and locking devices.
2. Description of the Prior Art
The problems associated with the servicing of large outdoor signs have long been recognized. Such signs are most often too narrow to permit walkways within the sign for internal maintenance such as cleaning, electrical and mechanical repairing, and the replacement of lights. Because of the physical dimensions and weight of front panels, they are most often divided into a series of smaller panels which may be detached by the serviceman. While allowing proper maintenance, the many paneled sign is extremely cumbersome, and removing the panels is very time consuming as well as dangerous where height is involved. Physically removing the panels is not possible on windy days.
Prior art patents such as Bauers et al, U.S. Pat. No. 2,512,515 and Covington et al, U.S. Pat. No. 2,512,519 illustrate sign opening devices utilizing counterweights and crank and pulleys for lowering the sign face. Such devices allow complete and often unwanted exposure to the entire inner surface of the sign, have bulky opening and closing elements, present problems of proper alignment and replacement of the front panel, and are therefore generally undesirable and of little practical value.